Aeroplane propeller



u. a. HARKINS. AEROPLANE PROPELLER.

. APPLICATION FILED FEB. 28,192I- 1,407,271 Patented FBI). 21, 1922.

3 SHEETS-SHEET 2- .23. G. j/arhkzs.

0. e. HARKINS. AEROPLANE PROPELLER.

APPLICATION FILED FEB. 28, I921.

Patented Feb. 21, 1922.

3 SHEETSSHEET 3.

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UNITED m rarestorrice.

DONALD HARKIN S, 01 CANTON, NORTH CAROLINA.

AEROPLAN E PROPELI'ER.

To all whom it may concern."

Be it known that I, DONALD G. HARKINS, a citizen of the United States, residing at Canton, in the county of Haywood and State of North Carolina, have invented new and useful Im rovements in Aeroplane Propellore, of which the following is a specification.

One object of my present invention is the provision of an aeroplane blade formed of wood and metal in laminated fashion and in such mannerthat the blade is, at once, light in weight and strong, and, therefore, well adapted to withstand the usage to which aeroplane propeller blades are ordinarily subjected. v i

' Another object is the provision of an aeroplane propeller blade mounted in improved manner for turning of the blade about its axis and relatively to its hub'without diminishing the strength of the connection between the blade and hub.

Another object is the provision in an aero plane propeller of improved means whereby the hub and the blades are connected to-' the plane indicated by the line 33 of Fig-- ure 1.

Figures 4, 5 and 6 are cross sections on the lines 44, 55 and 6 6, respectively, of

Fi ure 3.

igure 7 is an enlarged perspective of the inner end portion of one of the outer metal plates of the improved blades.

Figu intermediate metal plates of-the blades.

Figure 9 is a fragmentary perspective of one of the metalplat'es.

Figure 10 is a transverse section taken through one of the blades and showing the arrangement of the barbs of the interposed Specification of Letters Patent.

Application filed February 28, 1921.

re 8 is a similar view of one of the,

/ outer ends thereof in indentures 14 of the Patented'Feb. 21, 1922.

Serial No. 448,514.

metallic plates relatively to the edges of the wooden laminations of the blade.-

Similar numerals of reference designate corresponding parts in all of the views of the drawings.

The hub 1 is of metal and is provided with a taper bore 2 and a key-way 3 in the wall of the bore, to receive a. crank shaft 4 and its key; 5; the hub being secured on the shaft through the medium of a nut 6, Figure 2, or other appropriate means. tions of the hubl and reaching to one side thereof, Figures 3 and 4, are chambers 7 V which are closed at said side through the medium of closure plates 8, detachably connected to the hub through the medium of" lgg 14!; the ends of the hub and extending longitudi screws 9 or other appropriate means.

nally outward from the chambers 7 are openings 10, of circular form in CIOSS-SGCtlOIl,

which are surrounded -by inner and outer 7 circular grooves 11' and 12,'formed in the walls 13 of said openings 10. It will also be noted by comparison of Figures 3 and 5 that opposite sets ofshallow indenturcs 14. are formed in the walls 13. 1

The metallic heel members 15 of the blades 16 will be readily understood when it is stated that each of said members 15 is provided in its outer end with a blade socket 17,

and each is provided with an inner end portion 18, circular in cross-section 1n the present embodiment, and arranged and adapted to be turned about its axis in one, of the open- ;ings 10. A circular series of longitudinalbores 19 extends through each end portion 18, and each heel member 15 is provided in its shoulder 20 that'is opposed to one end of the hub 1 with a circular groove 21 which serves-with the groove 12 to form a race-- way for anti-friction balls-22. It will also be noted by reference to Figures 3 and 5 that the portion 18 of each heel member 15 is provided With a diametrical bore 23 cont-aining radially-movable plungers 24 betweenwhich is a coiled spring 25 which tends .to

thrust the said plungers 24 endwise outwardly and yieldingly maintain the rounded hub 1. This provision is made in qfller to avert casual rotation or change of position In the end-.por- 65 arms of the-heel-members 15 to adjust the pitchof the blades 16, the cooperating indentures 14 and plungers 24 will not prevent turning of the heel-members 15 and blades 16 about their axis.

Any suitable means may be employed to adapted to ride in a circumferential groove 62 formed in a slidable member 63 mounted on and movable longitudinally of the shaft 4. The slidable member 63 is also provided with a circumferential groove 64 spaced from the groove 62, and engaged with said groove 64 is a yoke 65 on which is a transverse rod 66 to which is connected an operating rod 67 designed to be under the control of an aviator. Q

Tn'the hub chambers 7 are arranged the anchor plates 30, Figures 1, 3 and 4. Manifestly when the plates, 8 are removed, said anchor plates 30 may be readily introduced edgewise into the chambers 7 and may then be shifted laterally. toward the ends of the hub 1 to position them on the blade bolts 31, it being understood in this connection that each plate 30 has a circular series of apertures 32 for said purpose; that each plate 30 has a circular groove 33' in its outer side to cooperate with a grooveli in forming a raceway for anti-friction balls 34; and that 'the inner ends of the bolts '31 are threaded for the'engagement of nuts 35 which are preferably wired on the bolts as indicated by 36 to preclude their casual loosening or displacement.

Each of the blades 16 is made up of laminations or sections 40 of wood, and alternate or interposed plates 41 of steel or appropriate metal. The plates 41 have oppositely directed lateral barbs 42 struck from them, and these barbs 42 are so relatively arranged, Figure 10, as to rest at considerable distances from the edges of the wooden sections 40; this being desirable for the sake of strength. It will also .be observed' that the striking of the barbs 42 from the plates 41 afiords transverse openings 43 in the plates for the reception of glue 44 through the medium of which adjoining wooden sections 40 are connected together and to the metallic plate 41 interposed between them. By comparison of Figures 6, 7 and 8 it will be understood that each of the outer plates 41 is provided with three comparatively small longitudinal threaded bores 50' in its inner end portion, and each of the intermediate plates 41 is provided with two relatively large bores head 70.

and its heel member being withdrawn as a unit from the hub.

The large and small bolts 31 are preferably arranged in a circle as shown for the convenient wiring of the nuts'thereon Figure 4.

Tn Figures 11, 12, 13 and 14 I show one means for adjusting the blades 16 about a common center and 'adjustably fixing the same. By particular reference to Figures 11 and 14 it will be understood that coupled to the arms 15 and extending rearwardly therefrom are connecting rods'60, the rear end portions of which are coupled to a cross- The web 71 pf the cross-head 70 is keyed on the shaft 4 as is also an annular disk 72 that is opposed toithe rear.-

side of the said. web 71. Keyed on the shaft 4 in rear of the cross-head 70 is a sleeve 73 with a flange 74 at its forward end; said flange 74 being opposed to the front side of the web 71 to receive headed .l threaded screws 75 which extend through the disk 7 2 and web 71 and strongly connect the same together and to the flange 74. It will be manifest from the foregoing that the cross-head 70 and the sleeve 73 and the parts connected therewith are susceptible of adjustment endwise of the shaft 4, notwithstanding they are caused in all positions to positively turn with the shaft when the latter is rotated.

The sleeve 73 is exteriorly of circular form in cross-section, and loosely receiving the said sleeve are collars 76 and 78 with opposed and spaced flanges 79 on their inner portions. Tnterposed between the collars 76 and 78 and loosely receiving the sleeve 73 and the collar flanges 79 is a cross-head 80. The said cross-head 80 does not rotate but is designed to be manipulated for the 91 with a hand lever 92, fulcrumed at 93 lever 92 is equipped with a detent 94 for cooperation with a segmental rack 95 fixedon the fuselage of the'aeroplane. The said on the fuselage. This provision is designed to enable an aviator to first adjust the blades about their common axis, and then adjustably fix said blades. 7

' l/Vhen the propeller blades are positioned as illustrated relatively to the, hub l and shaft 4, forward power will be afforded as is desirable when taking off or when in flight. When less power is desired as when touching. the ground in landing, the arms 15 are moved forwardly, Figure 2. In the illustrated example when the arms 15 'are moved forwardly by means such as herein-.

before indicated through ninety degrees, the pitch of the blades 16 will be changed to the extent of ninety degrees to afford a push instead of a pull.

Having describedmy invention, what I claim and desire to secure 'by Letters- Patent, is

1. An aeroplane propeller blade comprising wooden sections, and interposed metallic plates having barbs embedded in said sections.

'2. An aeroplane propeller blade comprising wooden sections, and interposed metallic plates having barbs embedded in said sections and also having openings for the reception of glue between the wooden sections. 3. An aeroplane propeller blade comprising wooden sections, and interposed metallic plates having barbs embedded in vsaid sections and also having openings for the re-' ception of glue between the wooden sections; sald barbs struck from the plates whereby openings are formed in the plates for the reception of glue interposed between the.

wooden sections.

4. An aeroplane propeller'blade comprising wooden sections, and interposed metallic plates having barbs embedded in said sections and also having openings for the reception of glue between the wooden sections;

"thesaid barbs being arranged remote from the edges of the wooden sections and therefore in the strongest portions of said sections.

5. An aeroplane propeller blade comprising wooden sections, and metallic plates interposed between and connected with the interposed between and connected with the wooden sections and having longitudinal .bolts at their inner ends and extending longitudinally beyond the inner end "of the blade; said bolts being threaded in longitudinal threaded bores in; the inner end portions of the plateshg 7. An aeroplane propeller blade com using wooden sections, and metallic p ates interposed between and connected with the wooden sections and having longitudinal bolts at their inner ends and extending longitudinally beyond the inner end of the blade; said bolts being threaded in longi tudinal threaded bores in the inner end' portions of the plates, and the outer plates being each provided with small bores and bolts, and the intermediate lates being each provided with a plurality of large bores and bolts.

8. An aeroplane propeller blade coin 'rising wooden sections, and metallic p ates" interposed between .and connected with the wooden sections and having longitudinalbolts at their inner ends and extending longitudinally beyond the inner end of the blade, in combination with a heel member having a socket receiving the inner end portion of the blade and'also having longitudinal bores extending inwardly from said socket and receiving the bolts, and means on the inner end portions of the bolts, anchoring the blade to the heel member.

9. An aeroplane propeller blade comprising wooden sections, and metallic plates interposed between and connected with the wooden sections and having-longitudinal bolts at their inner ends and extending longitudinally beyond the inner end of the blade, in combination with a heel member having. a socket receiving the inner end portion of the blade and also having longitudinal 'bores extending inwardly from said socket and receiving the bolts, means on the inner end portions of the bolts, anchoring the blade to the heel member, the hub receiving the inner portion of the heel memher and cooperating with said anchoring in combinatlon with a heel member having a socket receiving the inner end portion of.

the blade and also having longitudinal bores extending inwardly from said socket and receiving the bolts, means on the inner end portions of the bolts, anchoring the blade to the heel member, the hub receiving the inner portion of the heel member and cooperating with said anchoring means in holding the heel member and blade to the hub; the anchoring means being'in the form of a plate receiving the bolts and secured thereon, and the hub having a chamber extending to one of its sides for the introduction of said plate and also having means to normally close said chamber,

11. An aeroplane propeller blade comprising wooden sections, and metallic plates interposed between and connected with the wooden sections and having longitudinal bolts at their inner ends and extending longitudinally beyondthe inner end of the blade, in combination with a heeL member having a socket receiving theinner end portion of the blade and also havmg longitudinal bores extending inwardly from said socket and re ceiving the bolts, means on the inner end portions of the bolts, anchoring the blade to the heel member, the hub receiving the inner portion of the heel member and cooperating with said anchoring means in holding the heel member and blade to the hub; the said inner portion of the heel member and the hub bore being of circular cross-section, and the heel member being provided with means for the turning thereof about its axis.

12. An aeroplane L-propeller blade comprising wooden sections, and metallic plates interposed between and "connected with the wooden sections and having longitudinal bolts at their inner ends and extending longitudinally beyond the inner end of the blade, in combination with a heel member having a socket receiving the inner end portion of the blade and also having longitudinal bores extending inwardly from said socket and re .ceiving the bolts, means on the inner end portions of the bolts, anchoring the blade to the heel member, the hub receiving the inner portion of the heel member and cooperating with said anchoring means in holding the heel member and blade to the hub; the said inner portion of the heel member and the hub bore being of circular cross-section for the turningof said heel member and blade.

about their axis, and the heel member being provided with a spring-pressed detent, and the bore Wall of the hub with shallow in; dentures to prevent turning of the heel member and blade except when said heel member is subjected to stress.

13. Anaeroplane propeller comprising a hub, a plate, a heel member carried by the blade and iournaled to turn about its axis in the hub, and yielding means cooperating with the heel member and hub to prevent turning of the blade and 'heel member except when the latter is subjected to stress.

14. In an aeroplane propeller, the combination of a hub having a chamber reaching to one of its sides and also having a bore,-

T detachable means normally closing said terposed between and connected with the Wooden sections and having longitudinal bolts at their inner ends and extending longitudinally beyond the inner end of the blade, in combination with a heel member having a socket receiving the inner end portion of the blade and also having longitudinal bores extending inwardly from said socket and receiving the bolts, and means on the inner end portions of the bolts, anchoring the blade to the heel member; the heel member having countersinks in its inner end, and the bolts having enlargements disposed in said countersinks. I

llntestimony whereof, I aflix my signature.

DONALD s. nanirnts. 

